Mariniplasma anaerobium gen. nov., sp. nov., a novel anaerobic marine mollicute, and proposal of three novel genera to reclassify members of Acholeplasma clusters II–IV

Abstract

A novel strictly anaerobic chemoorganotrophic bacterium, designated Mahy22T, was isolated from sulfidic bottom water of a shallow brackish meromictic lake in Japan. Cells of the strain were Gram-stain-negative, non-motile and coccoid in shape with diameters of about 600–800 nm. The temperature range for growth was 15–37 °C, with optimum growth at 30–32 °C. The pH range for growth was pH 6.2–8.9, with optimum growth at pH 7.2–7.4. The strain grew with NaCl concentrations of 5% or below (optimum, 2–3%). Growth of the strain was enhanced by the addition of thiosulfate. The major cellular fatty acids were C16:0 and anteiso-C15:0. Respiratory quinones were not detected. The complete genome sequence of strain Mahy22T possessed a 1 885 846 bp circular chromosome and a 12 782 bp circular genetic element. The G+C content of the genome sequence was 30.1 mol%. Phylogenetic analysis based on the 16S rRNA gene revealed that the novel strain belonged to the family Acholeplasmataceae , class Mollicutes . The closest relative of strain Mahy22T with a validly published name was Acholeplasma palmae J233T with a 16S rRNA gene sequence similarity of 90.5%. Based on the results of polyphasic analysis, the name Mariniplasma anaerobium gen. nov., sp. nov. is proposed to accommodate strain Mahy22T, along with reclassification of some Acholeplasma species into Alteracholeplasma gen. nov., Haploplasma gen. nov. and Paracholeplasma gen. nov.

Paracholeplasma manati sp. nov. isolated from Florida manatees (Trichechus manatus latirostris)

“…The 16S rRNA gene sequence of Oakley T shared highest nucleotide identity (97.82 %) only with the 16S rRNA gene of Paracholeplasma vituli FC 097-2 T and lower nucleotide identity with the type strains of other phylogenetically related species within the family Acholeplasmataceae [1, 2], i.e., 96.36 % to Paracholeplasma morum 72-043 T , 95.34 % to ' Paracholeplasma brassicae ' 0502, 91.92 % to ' Alteracholeplasma palmae ' J233, 90.71 % to Mariniplasma anaerobium Mahy22 T , 90.33 % to Alteracholeplasma parvum H23M T and less than 90 % to the 16S rRNA gene sequences of other species of the genera Acholeplasma, Alteracholeplasma , Haploplasma, Paracholeplasma and Mariniplasma with validly published names available in GenBank. Therefore, the 16S rRNA gene sequence nucleotide identity of Oakley T to all known species within the aforementioned genera was below the proposed thresholds of 98.70 % [29] or 98.65 % [30] for this gene at the species level.…”

“…Currently, the family Acholeplasmataceae includes six genera: Acholeplasma, Alteracholeplasma , Haploplasma, Paracholeplasma, Mariniplasma ( M .) and Candidatus Phytoplasma [1]. On the basis of genomic and phylogenetic data, the last two genera are quite distant from other four genera [1].…”

“…The range of growth temperatures varies from 25 to 37 °C [4, 6, 8]. The phylogenetic relationship of the species of the genera Acholeplasma, Alteracholeplasma , Haploplasma and Paracholeplasma has been well studied [1, 2]. Most, if not all, of these species represent commensals of their host microbiota [6].…”

“…and Paracholeplasma ( P .) on the basis of the results of genomic and phylogenetic analyses [1, 2]. Currently, the family Acholeplasmataceae includes six genera: Acholeplasma, Alteracholeplasma , Haploplasma, Paracholeplasma, Mariniplasma ( M .)…”

“…and Candidatus Phytoplasma [1]. On the basis of genomic and phylogenetic data, the last two genera are quite distant from other four genera [1]. The species of the genera Acholeplasma, Alteracholeplasma , Haploplasma and Paracholeplasma are widely distributed in nature and can be detected and isolated from different plant, avian and mammalian sources [3–6].…”